Increase the buffer size if necessary before adding markers (#2838)

src/bgfx_p.h

@@ -2378,6 +2378,7 @@ namespace bgfx
 
 		void setMarker(const char* _name)
 		{
+			UniformBuffer::update(&m_frame->m_uniformBuffer[m_uniformIdx]);
 			UniformBuffer* uniformBuffer = m_frame->m_uniformBuffer[m_uniformIdx];
 			uniformBuffer->writeMarker(_name);
 		}